KR102077884B1 - Scatterometry overlay metrology targets and methods - Google Patents

Abstract

Scattering measurement overlay (SCOL) targets as well as methods of designing, producing and measuring are provided. SCOL targets have several periodic structures in different measuring directions that share some of their structural target elements or components thereof. The array of common elements may have a direction of symmetry parallel to the direction of measurement and thus miniaturizing the target or alternatively increasing the area usage efficiency of the target. Various configurations may increase flexibility in arranging multiple layers in the target and in the measurement direction and performing respective overlay measurements among the layers.

Description

Scattering Measurement Overlay Metrology Targets and Methods {SCATTEROMETRY OVERLAY METROLOGY TARGETS AND METHODS}

Cross Reference to Related Applications

This application claims priority to US Provisional Patent Application 61 / 827,717, filed May 27, 2013, which is incorporated herein in its entirety by reference.

Technical field

TECHNICAL FIELD The present invention relates to the field of metrology, and more particularly to scatter measurement overlay (SCOL) metrology targets.

Metrology targets are designed to quantify the correspondence between measurement of parameters indicative of the quality of a wafer production step and the design and implementation of on-wafer structures. Metrology targets as special structures optimize the requirements of device similarity and optical scalability. Scatterometry overlay (SCOL) targets are periodic structures used to produce diffraction patterns for metrological measurements. As the number of wafer layers increases and the available space for metrology targets decreases, there are certain requirements for more efficient use of target space.

One aspect of the invention comprises at least two periodic structures in at least two measurement directions, each of which comprises at least two types of periodically arranged target elements, at least one type of said target element being Provide a scatter measurement overlay (SCOL) target common to at least two of the at least two periodic structures.

The foregoing, additional, and / or other aspects and / or advantages of the invention are set forth in the detailed description which follows, and such aspects and / or advantages are possibly inferred from the description and / or may be learned by practice of the invention. Could be.

To better understand the embodiments of the present invention and to show how embodiments of the present invention work, reference is now made purely to the accompanying drawings, wherein like reference numerals refer to corresponding elements or sections throughout the drawings. Indicates.
1 is a high level schematic diagram of a SCOL target and resulting pupil plane scattering measurement images in accordance with some embodiments of the invention.
2 is a high level schematic of a SCOL target and resulting pupil plane scattering measurement images in accordance with some embodiments of the invention.
3A and 3B are conceptual high level schematic diagrams of SCOL targets and resulting pupil plane scattering measurement images in accordance with some embodiments of the invention.
4 is a high level flow diagram illustrating a method in accordance with some embodiments of the invention.

Before describing the description, it will be helpful to describe the definitions of certain terms used below.

As used herein, the term “measurement target” or “target” is defined as a structure designed or produced on a wafer used for metrology purposes. As used herein, the term "target element" is defined as a feature within an individual target area or metrology target, such as a box, grating bar, and the like. The target element may be full or empty (gap) and may also be split. That is, the target element may include a plurality of small features that cumulatively constitute the target element. The target is cited as including the target elements, each "target element" is a feature of the target that is distinguished from its background, and the "background" is the target in the same layer or another layer (layer above or below the target element). Wafer area proximate the element. As used herein, the term "layer" is defined as any layer used in any step of the photolithography process. Examples of layers used in a non-limiting manner herein include a resist layer, a layer after etching, an oxide or oxide diffusion (OD) layer, a polysilicon (poly) layer, a contact layer, a via layer, and the like.

As used herein, the term "periodic structure" refers to any kind of structure designed or produced in at least one layer that exhibits a given periodicity. The periodicity is characterized by its pitch, ie its spatial frequency. For example, a bar as a target element can be produced as a group of parallel lines spaced from each other, thereby reducing the minimum feature size of the element and avoiding monotonous areas within the target. The target element may comprise segments of uniform shape or segments of varying shape, for example periodically alternating shapes. The segments of the target element can be shared with other target elements, for example target elements that participate in structures with different measuring directions.

The term "measurement direction" as used herein refers to the direction in which the periodic structure is periodically followed. For example, the measurement direction of the grid as a periodic structure is perpendicular to the target element (eg bar or divided bar) making up the grid. The term "array" as used herein refers to a two-dimensional set of elements that is substantially invariant under translation along at least two directions. As used herein, the term “symmetric direction” with respect to an array of elements refers to the direction in which the array is invariant under translation, ignoring the boundaries of the array (as related to the array as if the array is infinite).

As used herein, the term “segment” refers to any nondivided feature that is part of a (divided) target element. Segments, such as pivoting elements, may have specific shapes and specific spaces along themselves and in relation to nearby structures and elements. As used herein, the term “pivoting element” refers to a target element or segment thereof that is common to two or more periodic structures without any a priori limitations in terms of dimensions and shapes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Now in referring specifically to the drawings, the particulars shown are by way of example and only for illustrative purposes of describing the preferred embodiments of the invention, and are believed to be the most useful and easily understood depictions of the principles and conceptual aspects of the invention. Note that it is presented as a process of providing losing. In this regard, the details of the invention are not shown in more detail than necessary for a basic understanding of the invention, and the description taken with the drawings makes apparent to those skilled in the art how various aspects of the invention may be practically embodied.

Before describing at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of components described in the following description and illustrated in the drawings. The invention is applicable to other embodiments and can be practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

Scattering measurement overlay (SCOL) targets as well as methods of designing, producing and measuring are provided. SCOL targets have several periodic structures in different measuring directions that share some of their structural target elements or components thereof. The array of common elements may have a direction of symmetry parallel to the direction of measurement and thus miniaturizing the target or alternatively increasing the area usage efficiency of the target. Various configurations may increase flexibility in arranging multiple layers in the target and in the measurement direction and performing respective overlay measurements among the layers.

At least two periodic structures in at least two measurement directions, each periodic structure comprising at least two types of periodically arranged target elements, at least one type of said target elements being one of said at least two periodic structures A scatter measurement overlay (SCOL) target and associated target design file, and design, production, and measurement methods, which are common to at least two, are provided. Furthermore, it comprises at least two periodic structures in at least two measurement directions, each periodic structure comprising a plurality of periodically arranged target elements and an array of pivoting elements, each pivoting element associated with said respective periodic structure. A scatter measurement overlay (SCOL) target and associated target design file, and a design, production, and measurement method, are disposed between a pair of nearby target elements. Exemplary and non-limiting target designs that follow the design principles applicable to these SCOL targets and enable the design of multiple SCOL targets according to specific requirements are shown in FIGS. 1, 2, 3a and 3b below, all of which are It is considered part of this specification. The dimensions and spacing between the target elements and the diffraction images shown in the figures are both to be understood not as limiting the scope of the invention but as merely describing the design principles of the invention.

1 is a high level schematic diagram of a SCOL target 100 and the resulting pupil plane scattering measurement image 150 in accordance with some embodiments of the invention. FIG. 1 shows a SCOL target 100 comprising periodic structures 171, 172 in two measurement directions 101 (in this case represented by X ₁ and X ₂ perpendicular to each other). Each periodic structure 171, 172 includes two types of A and B, 171 A, 171B and 172A, 172B, respectively, of periodically arranged target elements 110, 120, 105. Type B (171B and 172B including element 105) is common to both periodic structures 171, 172 (ie, shared by periodic structures 171, 172). For convenience of non-limiting description, a common type of target element is called pivoting element 105.

Note that the pivoting element 105 contributes to the scatter measurement diffraction pattern and thus functions as a divided periodic structure in each direction. Pivoted element 105 may be introduced in any layer, for example in the final resist layer or in any other layer in front of the resist layer. Metrological measurements can be performed at any stage of production, for example after etching. In certain embodiments, the target 100 can be used to measure the overlay of the via layer with respect to the metal layer or contact layer.

In certain embodiments, the array of pivoting elements 105 may include two or more subarrays of pivoting elements 105 with each subarray located on a different layer. Each array may be used for scattering measurements between layers with or without additional target elements 110, 120, 130. In such embodiments, one or more arrays may include two or more subarrays that are measurable in one, two, or more directions. Such an array may be viewed as a divided bar (or other original continuous structure) modified by a split pattern to be measurable in two or more measurement directions.

It is also noted that at least three main characteristics of the pivoting element 105 can be configured and adapted in relation to the specification. One such characteristic is the array configuration of the pivoting element 105 and in particular its direction of symmetry, ie the direction in which the array is invariant under translation (when it relates to the array as if the array is infinite). Another property is the distribution of pivoting elements 105 between target layers, which determines the production relationship (physical, chemical and geometric parameters) between pivoting element 105 and periodic structures 171, 172. The third property is in the form of an individual pivoting element 105, which may have an axis of symmetry along at least some measuring direction X _{1 in} order to reach efficient packing and production of the pivoting element 105. Considerations and design principles regarding these characteristics are described in detail below in a non-limiting way of explanation.

The pupil image 150 shows the zeroth order diffraction signal 160 and the ± first order diffraction signals 161, 162 from the periodic structures 171, 172, respectively. In the same case as shown with the vertical measurement directions X ₁ , X ₂ , the target 100 can be measured in the x and y directions to yield simultaneous scattering measurements of both axes. In the example as shown, pivoting element 105 may be configured to contribute (depending on their dimensions and arrangement) to the scattering measurement diffraction pattern in either or both directions. In such a case, pivoting element 105 is a component of each periodic structure 171, 172, and each periodic structure 171, 172 is accordingly two types of target elements 110, 105 and / or 120, 105 each. In particular, in this case the pivoting element 105 may be configured as an element common (shared) to the periodic structures 171, 172 on both sides.

2 is a high level schematic diagram of the SCOL target 100 and the resulting pupil plane scattering measurement image 150 in accordance with some embodiments of the invention. 2 shows a SCOL target 100 including periodic structures 171, 172, 173 in three measurement directions 101 (denoted by X ₁ , X ₂ , X ₃ ). Each periodic structure 171, 172, 173 includes two types of A and B (171A, 171B; 172A, 172B and 173A, 173B, respectively) of periodically arranged target elements 110, 120, 130, 105 do. Type B (171B, 172B and 173B including element 105) is common to all three periodic structures 171, 172 and 173 as shown. However, in certain embodiments, type B may be common to a subset of layers. In certain embodiments, other Type B elements can be designed in different layers. For convenience of non-limiting description, the common types of target elements are called pivoting elements 105.

As mentioned above, pivoting element 105 may contribute to the scatter measurement diffraction pattern and thus function as a divided periodic structure in each direction. As above, any suggested property of the pivoting element 105, i.e., the array configuration and symmetry direction of the pivoting element 105, the distribution of the pivoting elements 105 between target layers, and the shape of the individual pivoting element 105 Can be configured and adapted in connection with the

The pupil image 150 shows the zeroth order diffraction signal 160 and the ± first order diffraction signals 161, 162, 163 from the periodic structures 171, 172, 173, respectively. In the case as shown, the target 100 can be measured in the measurement direction of X ₁ , X ₂ , X ₃ to yield simultaneous scattering measurements of all three axes. The pivoting element 105 is a component of each periodic structure 171, 172, 173 consisting of two types of target elements 110, 105; 120, 105; and / or 130, 105 respectively. And scatter scattering diffraction patterns in the direction (depending on their dimensions and arrangement). In particular, pivoting element 105 may be configured as an element common to all periodic structures 171, 172, 173, or generally as a common element of some or all periodic structures within a given target.

Pivoted element 105 may be interspacing between adjacent target elements 110, 120, 130 of periodic structure 171, 172, 173, respectively. Space spacing may be full, ie there may be no overlap between pivoting elements 105 adjacent to target elements 110, 120, 130, or space spacing may be partial, ie some overlap May be acceptable. In some cases or for a given pivoting element 105, the overlap with other target elements 110, 120, 130 may be substantial or complete depending on the target design and the metrological measurements required. The array of pivoting elements 105 may be uniform throughout the target 105, or the array may include sub-regions with other characteristics of the pivoting element 105.

3A and 3B are high level schematic diagrams of a SCOL target 100 and the resulting pupil plane scattering measurement image 150 in accordance with some embodiments of the invention. 3A and 3B show a SCOL target 100 including periodic structures 171, 172, 173 in three measurement directions 101 (indicated by X ₁ , X ₂ , X ₃ ). For the periodically arranged target elements 110, 120, 130, 105, each periodic structure 171, 172 includes two types A and B (171A, 171B and 172A, 172B, respectively) and the periodic structure ( 173 includes type A 173A in FIG. 3A and two types A and B in FIG. 3B (173A and 173B, respectively). Type B (171B, 172B, and 173B including element 105) is common to all three periodic structures 171, 172, 173 as shown. Furthermore, in the case as shown, the elements 105 shown in hexagons are, for example, elements 171B and 172B (measurement directions X ₁ and X ₂ , respectively) in FIG. And 3 types of divided target elements 110, 120 common to two or three target elements as elements 171B, 172B and partially 173C (measuring directions X ₁ , X ₂ and X ₃ , respectively) in FIG. Is shown. The pivoting element 105 participates in building the target element as shown by the target element 173B in FIG. 3B, which pivot element 105 and the square target element are shown in alternating hexagons. It consists of a segment (110). The size of any element and the space between the elements can be calculated according to geometric and optical considerations, and FIGS. 3A and 3B serve merely as schematic conceptual descriptions without any intention of limitation.

Any target type, which may be three or more, may be common to a subset of target elements and / or a subset of layers. In certain embodiments, other types of B elements can be designed in different layers. For convenience of non-limiting description, the common types of target elements are called pivoting elements 105. Depending on the target design considerations and the pivoting element 105, several types of pivoting element 105 may be used. In certain embodiments, the array of pivoting elements 105 may include two or more subarrays of pivoting elements 105 with each subarray located in a different layer. Such an array can be used for scattering measurements between layers with or without additional target elements 110, 120, 130. For example, in FIG. 3A, any array 105, 110, 120 can be designed in multiple layers, and each element can be used to perform scattering measurements with respect to these layers.

In certain embodiments, pivoting element 105 may be produced after some or all of other target elements 110, 120, 130, for example, to ensure accurate positioning of pivoting element 105.

The pivoting element 105 can have a symmetry direction corresponding to the measurement direction. For example, in the case shown, pivoting element 105 is square (FIG. 1), circular (FIG. 2), hexagon (FIG. 3A, FIG. 3B), or the like. The measuring direction may be at right angles (eg 90 ° as shown in FIG. 1) or at any angle, for example 30 °, 45 °, 60 ° or any other depending on measurement and production considerations. Angles (see, eg, FIGS. 2, 3A, 3B). In certain embodiments, any depicted target may have 180 ° rotational symmetry. The targets 100 may have one, two, three or more reflective symmetries. That is, the targets 100 may be reflection symmetrical with respect to the plurality of reflective surfaces passing through the target 100. The targets 100 may have rotational symmetry of 30 °, 45 °, 60 ° and / or 120 °. Any pitch, measurement wavelength, and pupil plane parameters of the periodic structure can be adjusted to the measurement specifications needed to maintain the required measurement order within the pupil plane. Metrological measurement may include blocking a predetermined order at a predetermined measurement step. In certain embodiments, the illumination is not annular and may be a dipole, quadruple or other type of illumination. The illumination type and illumination direction can be adjusted according to the symmetry considerations regarding the target 100 and with respect to the measurement direction X _i of the target. In certain embodiments, the design details and measurement direction X _i of target 100 may be configured according to a given parameter, direction and pattern of illumination.

As mentioned above, pivoting element 105 may contribute to the scatter measurement diffraction pattern and thus function as a divided periodic structure in each direction. As above, any suggested characteristic of the pivoting element 105, namely the array configuration and symmetry direction of the pivoting element 105, the distribution of the pivoting elements 105 between target layers, and the shape of the individual pivoting element 105 Can be configured and adapted in connection with the

The pupil image 150 shows the zeroth order diffraction signal 160 and the ± first order diffraction signals 161, 162, 163 from the periodic structures 171, 172, 173, respectively. In the case as shown, the target 100 can be measured in the measurement direction of X ₁ , X ₂ , X ₃ to yield a simultaneous scatter measurement of two or three axes. The pivoting element 105 is then optionally made into a component of each periodic structure 171, 172, 173 consisting of two types of target elements 110, 105; 120, 105; and / or 130, 105, respectively. It can be configured to contribute (depending on their dimensions and arrangement) to the scattering measurement diffraction pattern in the direction of the number. In particular, pivoting element 105 may be configured as an element common to all periodic structures 171, 172, 173, or generally as a common element of some or all periodic structures within a given target.

Pivoted element 105 may space between adjacent target elements 110, 120, 130 of periodic structure 171, 172, 173, respectively. Space positioning may be full, ie there may be no overlap between the pivoting elements 105 adjacent to the target elements 110, 120, 130, or space positioning may be partially, ie some overlap depending on the particular requirements. May be allowed (see, eg, FIG. 3B). In some cases or for a given pivoting element 105, the overlap with other target elements 110, 120, 130 may be substantial or complete depending on the target design and the metrological measurements required. The array of pivoting elements 105 may be uniform throughout the target 105, or the array may include sub-regions with other characteristics of the pivoting element 105.

The target 100 may be based on a given model of SCOL target that is modified according to the principles described above for other purposes, such as improving productivity, simplifying the target, adding measurement directions, and the like. For example, certain periodic structures of an existing target are converted into an array of pivoting elements 105 and condensed with each other until the pivoting elements 105 become common elements of other periodic structures, ie at least partially overlap. Can be.

Any target element 110, 120, 130, 105 may be applied as a positive element or a negative element. Any target element 110, 120, 130, 105 may be full, gap (gap in filled background or divided background), or divided, i.e., composed of smaller segments. The pitch of any divided pattern, in particular the pitch of divided patterns in different regions of each layer, can be varied. The order of the layers and the periodic structure is non-limiting and can be modified according to the specific target design. The periodic structures 171, 172, 173 may be on each separate layer, or any periodic structure may be on the same layer. Obviously four or more periodic structures can be designed in the target 100. Pivoted element 105 may be in a single layer or in multiple layers, and there may be no complete overlap, partial overlap or overlap between pivoted elements 105 of other layers.

Target design files for producing target 100 are likewise considered as part of the present invention, such as any design modifications performed to make the conceptual design described herein compatible with production design rules. Scattering measurements of any SCOL target 100 described herein, particularly co-scattering measurements in other directions of the pupil plane, are also part of the present invention.

The method comprises the step of constructing a pivoting element selected from a plurality of target elements of an SCOL target to be common to at least two periodic structures with different measuring directions. The method may also include generating a target design file of each SCOL target, wherein the target design file is generated according to the method of the present invention. The method may also include producing a SCOL target, wherein the SCOL target is produced according to the method of the present invention. The method may further comprise aligning the at least two periodic structures in accordance with the pivoting element. The method may also include measuring diffraction patterns of the SCOL target produced by the method of the present invention and scattering measurements resulting from the SCOL target.

The method may also comprise configuring the pivoting element as an array with a direction of symmetry parallel to the measurement direction. The method may also include spacing adjacent target elements of the at least two periodic structures by the pivoting element. The method may also include designing a pivoting element in a target layer having a periodic structure, and producing (but not necessarily each) a pivoting element in one or more layers by one or more exposures. The method may also include configuring at least two periodic structures to create separate first order diffraction patterns at the pupil plane of the particular measurement tool.

4 is a high level flow diagram illustrating a method 200 in accordance with some embodiments of the invention. Method 200 may include designing and / or producing target 100 in any order, such as any of the following steps. Any design and configuration step may be executed by at least one computer processor. Certain embodiments include a computer program product including a computer readable storage medium embodied with a computer readable program. The computer readable program may be configured to execute the steps of the method 200. There is also provided a design file produced according to each step of method 200. Certain embodiments include a computer program product including a computer readable storage medium embodied with a computer readable program. The computer readable program may be configured to perform metrological measurements of any target produced according to the target 100 or method 200.

The method 200 includes providing an array of pivoted elements (step 210), using the array of pivoted elements as a periodic structure in at least two layers (step 220), and each periodic structure in a separate measurement direction. Designing in several layers (step 230) and selecting a measurement direction for the parallel symmetry direction of the array of pivoted elements (step 240).

In certain embodiments, the method 200 includes designing the array to include the periodic structure in the overlay measurement direction (step 212), configuring the pivoting element to have a particular symmetry relative to the geometry of the periodic structure (step 214). And / or selecting the pivoting element to be common to the at least two periodic structures (step 216).

In certain embodiments, the method 200 may include configuring (step 225) the direction of symmetry of the pivoted element and array in accordance with the overlay measurement specification. In certain embodiments, the method 200 includes spacing adjacent target elements of at least two periodic structures by a pivoting element (step 226) and / or positioning the pivoting elements in the space of the periodic structure of all layers. It may include a step (step 235).

The method 200 may also include designing a periodic structure and / or array (step 245) to produce a plurality of (at least first order) diffraction signals along each direction at the pupil plane. The method 200 may also include generating a corresponding target design file and producing a SCOL target (step 250).

The method 200 also includes extracting overlay data from several layers of a single target (step 260), eg, measuring overlay data simultaneously from different layers (step 261) and / or sequentially from different layers. Measuring overlay data (step 262). The method 200 may also include producing an array of pivoted elements by a plurality of exposures (step 255) and extracting overlay data in association with the corresponding exposure (step 265).

In certain embodiments, the pitch of pivoting elements 105 in the array in any symmetry direction may be between 200 nm and 2000 nm.

Advantageously, the target 100 can be designed to include several layers and to enable single or multiple measurements for one or more target cells. Moreover, the overlay can be measured among any target layer subset (eg, overlay of one or more layers with respect to one or more layers). Target configuration reduces the size of the area occupied by the target (or, alternatively, allows the use of larger targets in a given area), reduces measurement time, and executes multiple measurements on a single target. To improve.

In the foregoing description, the embodiments are examples or implementations of the invention. The various appearances of "one embodiment", "embodiment", "predetermined embodiment" or "some embodiments" are not necessarily all referring to the same embodiment.

Although various features of the invention may be described in connection with a single embodiment, the features may also be provided separately or in any suitable combination. On the contrary, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be embodied in a single embodiment.

Certain embodiments of the invention can include features from other embodiments described above, and certain embodiments can incorporate elements from other embodiments described above. The description of elements of the invention in connection with a particular embodiment is not limited to being used only in that particular embodiment.

In addition, it is to be understood that the invention may be practiced or carried out in various ways, and that the invention may be embodied in certain embodiments other than those described above.

The invention is not limited to the accompanying drawings or their corresponding description. For example, the flow diagram need not proceed through each illustrated block or state or in the exact same order as shown and described.

Meanings of technical and scientific terms used herein have the meaning commonly understood by those skilled in the art to which the present invention belongs unless otherwise defined.

While the invention has been described with reference to a limited number of embodiments, this description should not be construed as limiting the scope of the invention, but rather as an illustration of some preferred embodiments. Other possible variations, modifications, and applications may also be within the scope of the invention. Accordingly, the scope of the invention should not be limited to the description of the foregoing embodiments, but should be limited by the appended claims and their legal equivalents.

Claims (28)

For a scatterometry overlay (SCOL) target,
A periodic structure comprising a plurality of target elements configured for measurement in a first measurement direction; And
A plurality of pivoting elements disposed between the plurality of target elements,
The SCOL target is implemented at the first layer,
The plurality of pivoting elements are aligned with the plurality of pivoting elements in the second SCOL target when the SCOL target and the second SCOL target implemented in the second layer are angularly offset from each other. A scatter measurement overlay (SCOL) target. The scatter measurement overlay (SCOL) target of claim 1, wherein the target elements are segmented. The scattering measurement overlay (SCOL) target of claim 1, wherein the pivoted elements have symmetry corresponding to the measurement direction. The scattering measurement overlay (SCOL) target of claim 1, wherein the pivoting elements are circular. The scattering overlay (SCOL) target of claim 1, wherein the SCOL target and the second SCOL target are angularly offset from each other by one of 30 °, 45 °, 60 ° and 90 °. The plurality of pivoting elements of claim 1, wherein the plurality of pivoting elements are also angularly offset relative to each other when the SCOL target, the second SCOL target, and the third SCOL target are angularly offset from each other. And a scatter measurement overlay (SCOL) target. The scatter measurement overlay (SCOL) target of claim 1, wherein at least some of the target elements are segmented. The scattering measurement overlay (SCOL) target of claim 1, wherein the periodic structure and the plurality of pivoting elements are configured to produce a discrete first diffraction pattern in the pupil plane of a designated measurement tool. For a scatter measurement overlay (SCOL) target,
A first periodic structure comprising a plurality of target elements configured for measurement in a first measurement direction;
A second periodic structure comprising a plurality of target elements configured for measurement in a second direction; And
A plurality of pivoting elements disposed between the plurality of target elements,
The SCOL target is implemented at the first layer,
Wherein the plurality of pivoting elements are configured to align with the plurality of pivoting elements in the second SCOL target when the SCOL target and the second SCOL target implemented in the second layer are angularly offset from each other. , Scatter measurement overlay (SCOL) target. 10. The scattering measurement overlay (SCOL) target of claim 9, wherein the first and second measurement directions are any of 30 °, 45 °, 60 ° and 90 °, respectively. 10. The scatter measurement overlay (SCOL) target of claim 9, further comprising a third periodic structure comprising a plurality of target elements configured for measurement in a third direction. 10. The scattering measurement overlay (SCOL) target of claim 9, wherein the pivoting elements have a symmetry direction corresponding to the measurement direction. 10. The scatter measurement overlay (SCOL) target of claim 9, wherein the pivoting elements are circular. 10. The scatter measurement overlay (SCOL) target of claim 9, wherein at least one of the target elements is segmented. 10. The scattering measurement overlay (SCOL) target of claim 9, wherein the first periodic structure, the second periodic structure and the plurality of pivoting elements are configured to generate a discrete first order diffraction pattern at the pupil plane of the designated measurement tool. A method for aligning two or more periodic structures in at least one scatter measurement overlay (SCOL) target, the method comprising:
A first plurality of pivoting elements disposed between target elements in a first periodic structure having a first measurement direction and a second plurality of pivoting elements disposed between target elements in a second periodic structure having a second measurement direction Aligning with pivoted elements,
And the first plurality of pivoting elements and the second plurality of pivoting elements are configured to align when the first periodic structure and the second periodic structure are angularly offset. The method of claim 16, wherein the first plurality of pivoting elements and the first plurality of pivoting elements have a direction of symmetry parallel to the measurement direction. The method of claim 16, wherein the pivoted elements are divided periodic structures. The method of claim 16, wherein the first periodic structure and the second periodic structure are disposed on separate target layers. The method of claim 16, further comprising generating a discrete first order diffraction pattern at the pupil plane of the designated measurement tool. 17. The method of claim 16, further comprising generating a target design file of the SCOL target. The method of claim 16, further comprising producing the SCOL target. A scatter measurement overlay (SCOL) target produced according to the method of claim 22. The method of claim 16 further comprising producing the pivoting elements by a plurality of exposures. The method of claim 16 further comprising measuring one or more diffraction patterns of the SCOL target. A computer readable storage medium embodying a computer readable program configured to perform the method of claim 16. delete delete

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